A conventional large-sized display device sounds by a loudspeaker mounted in a case of the display device, or by a loudspeaker encapsulated in a simple box body. Since such loudspeaker is generally mounted on a holder directly, there exist technical problems of lack of resonance of acoustic signals, poor acoustic fidelity and being difficult in achieving an effect similar to that of human voice. Therefore, it is a research and development focus of various manufacturers to improve the acoustic quality of the large-sized display device.